Title: Model Random Polyampholytes from Nonpolar Methacrylic Esters
Author: Kaur B; D'Souza L; Slater LA; Mourey TH; Liang SW; Colby RH; Ford WT
Journal: MACROMOLECULES, 2011, V44, N10 (MAY 24), P3810-3816
Abstract: Copolymerizations of nonpolar methacrylic esters followed by functional group conversions were employed to produce random polyampholytes. Random terpolymers of Solketal methacrylate (SMA):tert-butyl methacrylate (tBMA): N,N-dimethylaminoethyl methacrylate (DMAEMA) were prepared from 80:10:10 and 54:23:23 mol % mixtures of monomers by RAFT polymerization in 1,4-dioxane. The terpolymers were treated with iodomethane to convert the DMAEMA units to quaternary ammonium ions and then with concentrated aqueous HCl/1,4-dioxane to convert the SMA units to glyceryl methacrylate units and the tBMA units to methacrylic acid units. H-1 NMR analyses of the unreacted monomers in reaction mixtures after partial polymerization and compositions of the terpolymers calculated from reactivity ratios support random structures for the terpolymers. H-1 NMR analyses of the polymers support complete conversions of the nonpolar monomer units in the terpolymers to ionic and hydrophilic monomer units in the polyampholytes. SEC analyses gave M-w/M-n = 1.3-1.4 for terpolymers having DPn < 300 and M-w/M-n >3 for terpolymers having higher DPn. SEC analyses of the derived polyampholytes gave M-w/M-n = 2.2-3.2 for all samples. Isoelectric points of polyampholytes were determined by potentiometric titrations and measurements of aqueous solution viscosity as a function of pH. © 2011 American Chemical Society.